$ git clone -n https://src.fedoraproject.org/rpms/libtrash.git /var/lib/mock/f40-build-2237999-53555/root/chroot_tmpdir/scmroot/libtrash
Cloning into '/var/lib/mock/f40-build-2237999-53555/root/chroot_tmpdir/scmroot/libtrash'...
$ git fetch origin eb5b783c716974c4e305ce5008db5aba29222775:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtrash
 * [new ref]         eb5b783c716974c4e305ce5008db5aba29222775 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at eb5b783 rebase to latest version